Coating machine for coating flexible sheets



Oct. 21, 1952 .w. 'r. SNYDER COATING MACHINE FOR COATING FLEXIBLE SHEETS 2 SHEETS-SHEET 1 Filed Sept. 22, 1948 4 1750572121- Z /[z'am TSTZyder A arrzey Oct. 21,1952 SNYDER 2,614,522

comma MACHINE FOR comm; FLEXIBLE SHEETS Filed Sept. 22, 1948 2 SHEETSSl-!EET 2 I Java-22157:- Jfi/l 'am TJnyder p/wn Patented Oct. 21, 1952 UNITED COATING MACHINE FOR COATING FLEXIBLE SHEETS WilliamT. Snyder, South Lancaster, Mass. Application September 22, 1948, Serial N 0. 50,537

2 Claims.

1 The present invention relates to improvements in coating machines, and more particularly to an apparatus for applying a liquid or semiliquid coating to a sheet material.

It is a primary object of the present invention 'to provide an improved means for applying a thin even coating of a liquid material to one or more surfaces of a substantially flat sheet, while the latter is being moved continuously, and without subjecting the sheet to any substantial fiexure or bending.

A further object of the present invention is to provide such an apparatus which is not only eflicient in operation, but which, at the same time, is adapted forhigh-speed operation.

' With the above and other objects in view, as will hereinafter appear, the'invention comprises the devices, combinations, and arrangementsof parts hereinafter set forth and illustrated in the accompanying drawings of apreferredembodiment of the invention, from which the several features of theinvention and the advantages attained thereby will be readily understood by those skilled in the art. I

In the accompanying drawings,

Fig. 1 represents a general perspective side view illustrating a coating apparatus in which the present invention is incorporated, and with one 2 tween a pair of cylinders 13 and which are provided, respectively, with shafts l5 and I5 suitably journaled within the side frame'members l and H. As will be hereinafter more fully described, the cylinders l3 and I4 are rotatably driven in'oppo site directions, as indicated by the arrows shown in Fig. 1. Furthermore, the cylinder [3 is rotated at a speed which is considerably less than'the speed of the cylinder It so that the" latter is adapted continuously to remove a thin even layer of the coating medium'from the reservoir 12.

Also rotatably mounted between the side frame elements l0 and H is a coating cylinder or roll 56 which is provided with a supporting shaft l'l. By referring particularly to Fig. 1, it is to be understood that the coating cylinder 16 is mounted in peripheral engagement with the oylinderld, so that-it will receive from the latter cylinder, an even layer of coating medium. In oneform of the invention, the cylinders 13' and I l are-con structed of metallic material, while the coating cylinder is provided with a rubber covered surface. V Positioned between the side frame elements In and H, and directly beneath and in parallelism with the coating cylinder 16, is an applicator roll, orcylinder, generally designated by side frame portion of the apparatus removed so as to illustrate the various component parts of the invention more clearly.

Fig. 2 is a schematic drawing illustrating the manner in which a portion of the coating apparatus is actuated. I 7 Fig. 3 represents a sectional view of a portion of the apparatus taken substantially along the line 3-3 of Fig. 1, and on an enlarged scale.

Fig. 4 represents a sectional view taken-substantially along the line 44 of Fig. 3. Y

Fig. 5 represents a side view, on the same scale as Fig. 1, and illustrating a modified form of the present invention.

Fig. 6 is a fragmentary sectional view illustrating a furthermodification of the invention.

Referring particularly to Figs. 1 and 3, the machine inwhich the present invention is incorporated, comprises a pair of oppositely disposed machine frame elements HI and II, the bottom portions of which are adapted to basecured upona floor. Carried between the frame elements 10 and H, .by any suitable means, such as rods l2, I2, is an open-bottom reservoir l2 which is adapted to contain a liquid coating-medium C. Referring particularly to Fig. 1, it is to be understood-that the reservoir I2 is fitted be:-

the numeral 18. Disposed at the right-hand end portion of the above described machine, is an endless conveyor belt 19 which is trained'over a pair of horizontally spaced conveyor rolls. and 21. The present invention contemplates the use'of a conventional conveyor belt system, and thus it is sufficient to state that the rolls'20 and 2| may be suitably journaled betweenthe' side frame elements l0 and H, and that any appropriate type of belt may be trained thereabout. Also, some form of driving mechanism, not. herein shown, may be employed for driving-the same in a manner such as'to deliver sheetmaterial from a supply source to the nip of the cylinders l6 and I8. I The present invention also contemplates the provision of a second conveyor belt 221which'is disposed at the left-hand side portion ofthe present machine, as viewed in Fig. 1. I This conveyor belt 22 may be trained over several horizontally spaced rollers 23, only one of which is illustrated herein. Suitable mechanism, not

herein shown, may be provided for driving this belt in a manner such that it may deliver sheet material from the nip of the cylinders 16 and I8 to any predetermineddestination.

One method of actuatingthe above noted cy1 inders l3, l4 and I6 is illustrated in Fig. 2. For example, the shaft I! of the cylinder l6 may have provided on one end portion thereof, a gear 24 which is constantly rotated in a clockwise direction by means of an electric motor 25 through the medium of a set of reduction gears 26 and 21. The cylinder I4 is adapted to be driven from the cylinder-shaft I! through a gear train which comprises a pair of similar interme's'hing idler gears 28 and 29. It is to be particularly noted that the gear 28 meshes directly with the gear 24, while the remaining idler gear 29 meshes directly with a driven gear 30 mounted directly upon the distal end portion of the cylinder shaft l5. The idler gears 28 and 29 are of the same size, so that the cylinder [4 is driven at the same speed as the cylinder [3. It is to be also noted that the cylinder 13 may be driven from the cylinder shaft l5 through the medium of a pair of similar idler gears 3| and 32. 3 meshes directly withfthe' driven gear 30, while the idler 32 meshes with a :large gear 33 carried upon the end portion of the shaft It provided on the cylinder l3. Due to the fact that the gear 33 is'large compared with the gear '32, it follows that the cylinder [3 will'be driven at asdbstantial ly slower speed than the cylinder 14. Thus, as hereinabove noted, this speed differential between the cylinders 13 and 14, will permit the latter cylinder to remove continuously and efficiently, a thin even layer of coating medium from the reservoir I2. I

-As will be hereinafter described, the applicator r011 18 is provided with a driving means which will function to rotate the roll in a counterclockwise direction. Thus, as the conveyor :belt it delivers sheets of material, generally designated by the numerals 34, 34 to the nip of the cylinders J8 and I8, the latter elements will grip the sheets so as to deliver them to the upper surface of the conveyor belt 22. In so transferring the sheets from one conveyor belt to the other, it will be understood that the cylinder IE will engage the top surface of each sheet as the sheet passes thereunder, so that an even layer of the coating 4 medium will be applied to the sheet without substantial fiex-ure or bending of the same. I I

As may be best understood by reference to Figs. 3 and {1, the applicator cylinder 18 is in the form on thin cylindrical shell 35, the surface of which is provided with a plurality of small apertures or air ducts 36, 36. This shell 35 is fitted snugly about the outer periphery of a nonrotating hollow cylinder 3! which is provided ateach end portion thereof with a ring of circumferentially spaced antifriction elements which, in a preferred embodiment of the invention; may take the form of bearing balls 38, 38. From this, it will 'be understood that the balls 38-, 38 function "as antifriction means which will perm-it the shell 35 to rotate freely about the element 31. Formed longitudinally across the upper surface of the element 3'! is a slot 39, and communicating directly with the inner portion of the cylinder is a conduit 40 connected to a conven'tional type of vacuum pump, not herein shown. From this, it will be understood that as the shell 35 is rotated about the element 31, various of the shell apertures 36, 36 will be shifted into register with the slot 33 to the end that a continuous suction will be formed along the upper surface of the shell as and directly beneath the cylinder 16. Thus, if the shell 35 is continuously rotated at a speed in synchronism with that of the cylinder 18 the various sheets 34, 34 will be grasped be- The idler tween the nip of the cylinders 16 and 35, and the vacuum will tend to hold the underside of the sheet, as the latter is delivered in a left-hand direction, as viewed in Fig. 4. In other words, with the above described mechanism in operation, each sheet 34 will be moved by the right-hand conveyor toward the rolls l6 and [8 until its leading edge reaches that portion ofthe perforated shell or suction roll 35 which is connected to the source of suction through the slot 39. When this occurs, the sheet is carried into engagement with the under surface of the coating roll l6, which applies a thin even layer of the coating medium to the top surface of the sheet. As the coated portion of the sheet moves toward the second conveyor, the suction is released as the sheet passes the left-hand edge of the slot 39, as viewed in Fig. 4, and the weight of the sheet with the coating thereon is sufiicient to cause the sheet to bend downwardly slightly until its lead- 'ing edge reaches the second conveyor belt. Aftor that, the following portion of the coated sheet passes readily onto the conveyor, which removes the sheet for drying the coating, or for "the 'performance of any other desired operation.

In order to prevent a sheet from following downwardly around the surface of the shell '35. a stationary doctor blade 41 is provided which engages the surface of the shell 35 adjacent to the left-hand edge of the slot 39, as viewed in Fig. 4. This doctor blade 41 may be mounted upon a shaft 42 which, in turn, may be supported within "the oppositely spaced frame elements It and I I.

As hereinabove noted, it is a primary obliec't of the present invention to coat a sheet without appreciably bending the same. Thus, the suction roll I8 is particularly designed so as 'to prevent the leading edge portion of each section of sheet material from adhering to the periphery of the coating cylinder [6. Obviously, since the coating material normally used has somewhat of an adhesive characteristic, it will tend to makethe leading edge of each sheet adhere to the surface of the cylinder [6, to the end that the sheet will wrap about the coating cylinder. However, by referring to Fig. 4 of the drawings, it will be un derstood that the slot 33 of the element '37 is wide enough so that the suction will strip "the leading edge of each sheet away from the sur face of the cylinder [6 as soon as the strip has emerged from the nip of the two cylinders l6 and I8. Heretofore, it was common practice to provide various types of unwieldy and inefficient mechanical elements for peeling the coated strips off of the coating roller. Clearly, suchprior mechanical means were not only inefficientin operation, but they many times produced defects in the coated material. The present suction roll obviates such defects entirely. I

In order to rotate the shell 35in sync'h'ron'is'm with the cylinder Hi, there is provided about the left-hand end portion (as viewed in 3) of the shell, 2. ring gear 43. Meshing 'withjthis ring (gear 43 is a pinion '44 carried upon the distal end of a shaft 45 which is driven by an electric motor 46. Referring particularly to Fig. '3, this electric motor 45 is carried upon a bracket T! which in turn is rigidly securedupon the lefthand end portion of the 'element 31. Thus, ro tation of the pinion 44 will driv'eth'e shell 35 in synchronism with the coating cylinder l3. Various well-known means may be employed for actuating the electric motors '25 and 46 in a proper speed ratio, so that the peripheral speeds oflthe coating cylinder I6 and the shell 35 will 49, 49 function to bias the roll assembly l8 toward the coating cylinder I6. Head portions 52, 52 of the studs 49, 49 function as stops which limit the uppermost position of the roll assembly. Provided :onthe lower threaded portions of the studs 49, 49 are lock nuts 53, 53 which function to prevent thestuds from becoming loose in the base 48. By. turning the heads 52, 52, the roll assembly may be adjusted with respect to the coating roll. Actually, the studs 49, .49 are so adjusted that the entire roll assembly 18 is positioned beneath the cylinder I6 so as to provide therebetween a space, the widthof which is slightly less than the minimum width of any one of the sheets 34, 34-. From this, it will be understood that the shell 35 will be continuously spring biased against the individual sheets 34, 34 as they pass between the nip of the coating cylinder [6 and the roll assembly I8. Also, this arrangement will insure that the shell 35 will never engage the periphery of the coating cylinder I6 .and thus, none of the coating medium willever be transferred to any portion of the roll assembly [8. I

Also carried upon each of the studs is a nut 54 which engages the lower end of a coil sprin so that by adjusting the nut along its stud, the biasing pressure between the rollers l6 and It may be varied. From the foregoing, it is apparent that the above described mechanism is adapted to apply an even coating to the surface of a flat sheet, without subjecting the sheet to any substantial bending or flexure which would distort the sheet,

6. action of the sheets, due to the fact that the sheet is forcibly biased against the periphery of the shell 35 by the suction action.

Whenever the coating roll I5 is rotated in a counterclockwise direction, the coating medium carried upon the periphery of the roll is applied upon the sheet material after the latter emerges from between the coating roll [6 and the ap-' plicator roll assembly 18, as represented by the rotatably driven shell 35. Thus, it will be under- I stood that-there will be no opportunity for the or tend to curl it. By spring biasing the shell 35 toward the coating cylinder Hi, there is insured an even application of coating, without any tendency to thin out the coating by the application of too much pressure as the sheet passes between the two cylinders. That is to say, by setting the distance between the cylinder I6 and the shell 35 to substantially the thickness of a sheet 34, the coating can be caused to flow readily onto the sheet from the coating cylinder I6. From this, it will .be understood that the suction roll l8 actually functions to pull each sheet from the conveyor and toward the nip of the two rollers, with the coating rollmerely following the movement of the sheet so as to apply an even coat of material upon the sheets upper surface.

.In the coating of certain types of sheets, I have found it to be desirable to reverse the direction of rotation of the coating roll It so as to produce a more uniform layer of coating medium upon theupper surface of such sheets. For example, by referring to Fig. 5, the coating roll [5 is' made to rotate in a counterclockwise direction, the same as the lower roll or shell 35.

It is to be understood, however, that such rotation of the coating roll will not have an adverse eifect upon the feeding action of the sheet material for, as hereinabove noted, the lower roll orjjshell 35 is entirely responsible for the feeding opposed surfaces of the rolls I6 and I8 to thin 1 out the layer of coating medium which is applied upon the sheet. Furthermore, by referring to Fig. 5, it will be understood that with thecoating roll I6 rotating in a counterclockwise; direction, the coating medium will tend to accumulate slightly in an area designated by the reference character C to theend that a uniform coating of the medium will be deposited over theupper surface of the sheet. Such an accumulation of coating medium insures that the entire surface of the sheet will be covered by'a layer of optimum depth and of extremely uniform thickness throughout. I

Referring now to Fig. 2, it is to be understood that whenever the coating roll I6 is to be rotated in a counterclockwise direction, the idler gears 28 and 29 are first removed from the driving mechanism and in lieu thereof, there is provided a single idler gear which is illustrated in dotted lines and designated by the numeral 55. Thus, the coating roll I5 may be readily rotated in a counterclockwise direction by substituting gear 55 for the idler gears 28 and 29, and thereafter reversing the direction of the motor 25. By so substituting the idler 55 for the two idlers 28 and 29, it will be manifest that the cylinders I3 and I4 will continue to rotate in the same direction as before, to the end that the coating medium will be properly removed from the reservoir i2 and applied to the surface of the coating roll I6.

With the coating roll I5 rotating in a counterclockwise direction, as described above with reference to-Fig. 5, in some instances it maybe desirable to delay the action of the applicator roll I8 in pressing a sheet 34 against the roll I5, until after the leading edge of the sheet to be coated has passed the lowermost point of tangency with the under surface'of the coating roll It. The purpose of such timing is to prevent the application of coating to the leading edge of the sheet, so that there will be anuncoated strip along the edge of each sheet, as delivered by the operation of the machine.

One way of accomplishing this result is indicated in Fig. 5, whereinthe entire applicator roll assembly is adapted to be maintained in a slightly retracted position in the interval between the ed on a rod 56 surrounded by a spring 51 that normally serves to engage the trunnion 50 and yieldingly maintain it in a position determined by thejen'gagement of a stop 58 on the rod with a frame member 59. With the stop 58-so en gaged, the roll I8 will yieldingly press the upper side of a sheet34 against the Each rod 56 extends belo'w its; stop I, 58 and "is surrounded by a solenoid to-which; when energized, will serve to pull the rod and its associated trunnion-50 downwardly against the 'pressure of the-spring 51, so that a sheet will not be heldin contact with the coating :roll 1-6 when the solenoid 60 is energized. one terminal of the solenoid so is connected to one oi'a pair of electrical supply mains oi, while the other "solenoid terminal is adapted to Ice-connected to the other supply main through the relatively movable contacts 62 and 63 of a Ire1ay, t'he operating winding 64 of which risadap'ted to be energized from a suitable photoelectric cell 65 located adjacent to the space between the rolls 1'6 "and is.

The photoelectric cell '65 is adapted to receive a beam of light as projected from a suitable lamp 66 -.located above the cell'tli, with the light ray being indic'ated by a dot and dash line in Fig. Therefore, as long as the "cell 65 receives light from theilam'p 66, the relaywinding 64 will remain energized to hold the contacts E2 and 63 closed, as indicated in dotted lines, and thereby energize the solenoids to, and exert a downward pull on the rods 56 which support the trunnions 50 of the roll assembly. id. However, when a sheet 34 is passing between thecoating roll it and the applicator roll 18, as indicated in Fig. 5, the projection of the light ray to the cell 65 will be interrupted, thereby deenergizing the relay winding '64 and opening the circuit of the solenoid G at thelrelay contacts 52 and 63, as indi cated in fullv lines in Fig. '5. Therefore, the solenoids '50 are deenergiZed-during most'ofthe time that the machine is in operation, so thatthe springs 51 are free to yieldingly urge theroll IS in the direction of the roll l6, with the distance between the peripheries of the rolls being determined by the engagement of the stops 58 on the rods 56 with the frame member 59.

It is to be noted that the light my, as projected by the lamp 66, is slightly ofiset from the lowermost point of tangency between a sheet 34 and the under surface of the coating roll [6. Therefore, when the trailing edge of the sheet shown as being coated in Fig. 5, clears the light ray, the resulting energization of the cell 65 will cause the (relay contacts 62 and 63 to close, as indicated in dotted lines, with the resulting energiza tion of the solenoids 60 causing the entir roll assembly 18 to be lowered slightly in advance of thearrival of the leading edge of the next unooated sheet at the coating roll l6. Consequently, as-the leading edge of the uncoated sheet arrives exactly beneath the coating roll it, the applicator roll l8 will still be in a retracted position, and the leading edge of the sheetwill not have any coating applied thereto, immediately.

However, as the leading edge of the sheet interru-pts the projection of the light ray to the cell: 55,, shortly after the edge has passed the lowermost point of tangency withthe roll Hi, the resulting deenerg-ization of solenoids 8d permits the springs '57, acting on the trunnions 59', to press the upper surface of the sheet into contact with the coated-surface of the roll !6. As a result, sheets 34 passing between the rolls .16 and I8, with the arrangement shown in Fig. will each have an uncoated' strip along one edge,

with the widthof the uncoated strips being de- 5 termined by theidisplacement between the projected light ray and the lowermost point of tangency on the under surface of the roll 16. Obviously, the above described arrangement for automatically retracting the applicator rolllB during the intervals between the departure pig-a coated sheet and the arrivalof an unc'oated sheet, can ib'e also applied to the mechanism sho'wn'in Fig. wherein the trolls l6 and .I8 are driven in opposite directions of rotation. Referring now to Fig 6, there is shown a furth'e'r modification of the inventio'n'wherein the applicator roll [8, as represented by the per forated shell 35, is replaced by a conveyor belt 61 that is driven by suitable means not shown, so as to move continuously beneath the coating roll it in the direction of the arrow. The belt '61 provides perforations 68, and the lower surface- 0f the belt is adapted to make close contactft'vith the upwardly extending -sides69 of a suction box 70, with rollers H being adaptedto support the belt along the sides 69-. The suction box 10 is connected to a suitablesource of suction, so that the belt 61 will tend to grip and hold sheets de livered to the belt for the purpose of having a coating applied thereto by the roll IS. The belt 6? is adapted to yieldingly maintain the upper surface of each sheet thereon in contact with the coating roll l6 through the action of a cylinder l2 located within the suction box 10, which cylinder i2 is mounted between trunnions 13 that are yieldingly urged in the direction of. the belt .61 in substantially the same manner asshowrr in Fig. 3, with reference to the cylinder 31-. With the modified arrangement shown in Fig. 6., it is obvious that the perforated belt 6'! will function in substantially, the same manner as the-perforated shell 35, in causing the, application of each sheet to the underside of the coating roll 16, without any possibility of the sheettending to follow around the surface of the roll l6, due to adhesive action of the coating as itiis'a'piplied to the sheet.

From the foregoing, it is apparent that by the present invention, there is provided an improved coating machine characterized by a numberof advantageous features not possessed by existing machines of the rotating cylinder type. For exeample, the machine of the present invention is able to coatsheet's of varying size and thickness without necessitatingany changes'in the mech= anism in advance of running the-different sheets, other than the previously described adjustment of the 'applicatorimember that determines the exact spacing between the; moving surfaces. or the roll [6 and either of the perforated applicator members [8 or 67. In this respechthei'machine of the present invention. differs radically from conventional coating machines of the :type wherein the sheets to be coated are carried around the surface of a large cylinder, with each change in the size or thickness of the sheets to be handled requiring a different make -ready." In the operation of the present machine, for. a given setting of the applicator roll assembly, as determined by the stops 52, sheets of varyingsize and thickness within a considerable range can be run through the machine successively, due to the yield'abl'e mounting of the entire assembly, which, howeveiyis always set so that the applicater member, as represented by thejperforated shell 35,01 the perforated belt 6'1, never touches the coating "ro-ll- IS in the intervalbetween the departure of a coated sheet and the arrival of an uncoated sheet at the point of tan'gen'cy with the undersurfac'e'of the roll I6. v Iclaim: I

1. Apparatus for coating flexible sheets com prising in combination, a rotatabl'y drivenrolli means for eupplyingooa-ting medium to the-sur :face of said roll, means forfeeding a sheet in flat condition to engage one surface thereof with the periphery of said coating roll, means for supporting said sheet in a flat condition beyond said coating roll, .a second roll having a perforated surfaca a hollow casing forxrotatably supporting said second roll and providing a port extending transversely to the direction ofmovement "of a, sheet and }in communication-with a porti'onof said perforated roll surface nzeans for rotatably driving said second roll around saidvcasingdmeans a for evacuating the interiorof said" casing sub"- ject the uncoated side of-a sheet to suction as it passes between said rolls within a zonedefined ,by the limited number'of perforations exposed to suction through said port,' to thereby strip said sheet from 'said coating roll as itcontinuesits movement in'a fiat condition ontosaid sheetsup-. porting means, and means for yieldinglysupportingsaidsecond roll, said evacuated casing, and said rolldriving means, asa nit, so as 'to urge that portion'of said roll in the vicinity of said port into engagement with the uncoated side [of a-sheetpassin'g between the rolls.

"2. Apparatus for coating flexible sheets com- "prisingsin combination, a rotatablydriven roll,

' means for supplying coating medium to'the sur face of said roll, means for feeding a sheet in flatcondition to engage one surface thereof with the periphery of said coating roll, means for supporting said sheet in a flat condition beyondsaid coating roll, a second roll having a. Perforated surface, a hollow casingfor rotatably supporting saidsecond roll and providing a port extending transversely to the direction of movement of a sheet andin communication with a portion of said perforated roll surface, means for rotatably driving said second roll around said casing,

means for evacuating the interior of said casing to subject the uncoated side of-a sheet to suetionas itpassesb'etween said rolls within azone defined by the limited number of perforations exposed to suction'through said port, to'thereby strip said'sheet from said coating roll as it continues its movement in a fiat condition onto said sheet supporting means, means for yieldingly' supporting-said secondiroll, saidevacu ated casing, and said roll driving means, as a unit, so as to urge that portion of said roll in the vicinity ofsaid port into-engagement with the uncoated side of a sheet passing between the rolls, and means responsive-to the passage of sheets between said rolls, for retracting said second r011 in advance of. the arrival of the leading edge 01' a sheet at said coating roll,iand for releasing said retracting means to cause coating of, said sheet at a predetermined distance from the uncoatedleading edge thereof. I

WILLIAM T. SNYDER.

' REFERENCES CITED The following references are of, record in the file of this patent: H 1

UNITED STATES PATENTS 

